The invention herein is directed to an implantable metered dose drug delivery system. More particularly, the implantable metered dose drug delivery system herein has utility in the treatment of pain associated with or brought about due to cancer and other similar diseases.
Many diseases and ailments which plague mankind also have associated with them pain and discomfort. For example, the presence of cancer can cause severe and intense pain for considerable time. Such pain is a great discomfort to the individual who must learn to tolerate the pain or take medication for alleviating the pain. In many instances, the administering of medication is unpleasant and can cause discomfort or undesirable side effects to other systems of the individual. In some instances, the medication is of short duration and thereby only of temporary relief to the individual. The systemic narcotic dose required for alleviation of severe cancer pain often leaves the patient drowsy and inactive. However, animal and human studies have shown that focal application of morphine in the spinal epidural or subarachnoid space results in pain abatement without depression of the central nervous system. Poletti et al describe a system for the focal application of morphine in J. Neurosurg., Vol. 55, pp. 581-584, October 1981.
It would be desirable to have an implantable drug delivery system which could be implanted in the body of an individual which could meter out the proper dosage of pain reliever to the spinal epidural or subarachnoid space to provide pain abatement. It would be desirable to have such a system which could be activated by the patient without the need to continually visit a physician.